Color-Doppler Ultrasonography to Predict the Moment of Ovulation in the Bitch

Abstract

T he domestic dog (Canis familiaris) is a non-seasonal monoestrus species that present spontaneous ovulation. The bitch's reproductive cycle is very typical, where significant variations do occur between and within dogs. The duration of the different phases of the cycle, such as pro-oestrus and oestrus can vary from 5 to 20 days and 6 to 11 days, respectively and, therefore, these variations explain poorly known breeding dates (Concannon, 2010). The fertile period can sometimes extend from 5 days before and after ovulation (Levy et al., 2007). On the other hand, the male's sperm lifespan is very short, and studies have shown that, after freeze-thaw, the percentage of motile and viable sperm decreases up to 45% (Thomassen et al., 2006). Hence, it become utmost important to precisely determine the date of ovulation. For subject matter, there are several techniques available to predict the time of ovulation, and these include vaginal epithelium exams, hormone dosage, or ovarian ultrasonography. Vaginal cytology determines the phases of the oestrus cycle. Supplemented with a hormone test, it is most often used to monitor the onset of the period when ovulation date approaches (Bouchard et al., 1991). However, due to variations in cycles between and within bitches, ovulation cannot be determined with precision by this method (Rosset et al., 2009). The LH blood test performed by radio-immunological method (RIA) or by ELISA test is another method to be used. However, owing the fact that blood LH surge has a short duration, its detection is so delicate to a point where it is often necessary to carry out daily blood tests (ideally two blood samples) until the surge detection (England et al., 2002; Levy et al., 2007). In addition, some studies have shown that the LH surge is sometimes biphasic where an initial rise needs not to be taken into account in determining the date of ovulation ( Jeffcoate and Lindsay, 1989